This is from steveX, he wasnt able to post it for some reason so i am putting this up for him.

Well since you guys turn my other post into a personal think, I will start a new one...lol.

OK, here is the write up on the a/c installation. most of the BLT parts are re-using in this installation, this also help keep the cost down.

first we will start with the a/c compressor. Has we know the l67 compressor can not be use with this a/c system, but we will us the clutch and pulley off the l67 compressor. you will need to use GM tool # J-33013-B (clutch remover and installer). this tool is a MUST. you can call 1-800-GM-TOOLS, for a FREE tool catalog. you will find all the tool you need to work on you GM car (any gm car).

if you notice the white connector on the compressor, this is for the a/c coil.
here is a pic of the BLT with its clutch and the L67 with the clutch off.http://photos.yahoo.com/bc/gnnext2003/v ... %26.view=t
the clutch and pulley laying on the side is from the BLT (not use).
once you have the clutch and pulley assemble, then you can bolt the BLT compressor into the engine braket (more pic on engine braket).

Next step is, we will need to install all the a/c line for the BLT. no l67 line is use here. here is what you will need to do, once you have the line all connected. remember you will need to install NEW O-ring on all the a/c line and at the compressor connection (part store). we are going to elimanate the BLT wiring for the a/c. the only thing we will keep is the A/C clutch relay. here is a pic.http://photos.yahoo.com/bc/gnnext2003/v ... %26.view=t

if you notice also in the first pic, you will see a plug with a yellow connector. this plug is for the a/c pressure sensor (L67). you will find this plug on you L67 engine wiring harness. it is located about 6 inches away from the PCM, two long connector. you will need to cut the three wire on this plug and extend it to the right side of the engine compartment. on the L67 a/c system this sensor in located on the left side engine compartment, right under the air cleaner. the reason you need to re-locate the sensor is because the BLT is on the right side engine compartment, in the high pressure a/c line. the stock BLT pressure sensor has two pin, you can not use this sensor, you must use the three pin sensor off the 97-2002 L67 a/c system ($29). you do not need to figure out any wiring here. but i will tell you what they are for.

they are three wire. GRAY, RED/BLK, and BLK

GRAY wire is 5 volt. this wire gose to the pcm. curcuit 474
RED/BLK wire is pressure signal to the pcm. curcuit 380
BLK wire is ground in the pcm. curcuit 452

all the wire on this sensor goes to the pcm. all you need to do is extend the wiring harness. so the plug can reach the right side of the engine compartment.

Now you will have a DK GRN/WHT (A/C compressor clutch request input)wire comming out of the pcm. on curcuit 762. this wire will go to the climate control unit inside the car. on the 89 BLT this wire will connect to the LT GRN wire behind this climate control.

this wire will connect to the LT GRN/BLK wire on the BLT A/C relay. the Lt BLU wire will need to be connected to the PNK/BLK wire on the relay, or you can wire it into the fuse block. this wire must only have 12 volt with the key ON.

now thats it for the wiring. all the other sensor is elimated from the BLT a/c line.

this is how the system will work now. when the driver turn the a/c on. the compressor clutch will engage. the pcm will look at the a/c line pressure. once the PCM see the a/c line pressure is too high it will dis-engage the clutch, when pressure drop to safe range, it will engage the clutch. this PCM montior the complete system, throught the a/c pressure sensor.

the kit is made by INTERDYNAMICS INc, MODEL # RKR-5,which is located in my hood (brooklyn N.Y. the kit come`s with three can of refrigerant (134a). in each can ,you have 12 oz of refrigerant, 3 oz oil, and a O-ring conditioner leak sealer. Low and High service port adapters. here is the low adapter:http://photos.yahoo.com/bc/gnnext2003/v ... %26.view=t
here is the high side adapter, red cap:http://photos.yahoo.com/bc/gnnext2003/v ... %26.view=t
these adapter screw right on to the BLT fitting.
the kit also come`s with the connector to charge the system. and thats it.
NO, YOU DO NOT NEED TO REPLACE THE R-12 LINE. un-less they are leaking.

once you have the system completely assemble, you will need to vacumm the system ( auto shop), and have a shop check for leaks. you can charge the a/c system your self, with the kit. it is very easy, just read the instruction in the box.

i fill the system with two cam of 12 oz 134a. when you charging the sytem you must turn the a/c ON, so once the a/c pressure sensor detect pressure, it will trun the compressor ON, so the Refrigerant can move throght the system. when the compressor turn On, the cooling fan should also turn on. only the little fan will tunr ON, the big fan will turn when the engine coolant temp reach operating temp. the BLT a/c capacity is 1.30 kg (2.87 lbs), this mean you will need 2 3/4 can of refrigerant.
That it, you L67 a/c 134a conversion (swap)

NOTE: i will not post this again. i recommend this topic be save and post in a different section. please Don`t bug me later on for all the infor on the a/c swap. i will only help with little tips, once you are doing the swap.